Mask for depositing and distributing reagents on an analytical support

ABSTRACT

The invention concerns a mask for distributing one or more reagents on an analytical support, in particular an electrophoresis support, for example an electrophoresis gel. The mask ( 10 ) (termed a mobile mask) held in a mask holder  12  is designed to be displaced above predetermined zones on an analytical support, and comprises traversing orifices  36  for distributing reagents on the analytical support.  
     The invention has application, for example, in the field of detecting and characterizing constituents present in a biological sample. In particular, detection can be accomplished by immunofixation.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a continuation-in-part of U.S. patentapplication Ser. No. 10/072,327, filed on Feb. 6, 2002, the contents ofwhich is hereby incorporated by reference herein.

[0002] The invention relates to a mask for depositing and distributingone or more reagents on an analytical support, in particular a supportfor electrophoresis, for example agarose gel.

[0003] The invention is suitable for use, for example, in the field ofdetecting and characterizing constituents present in a biologicalsample, in particular a biological liquid such as serum, urine orcerebrospinal fluid. In particular, such detection can be carried outfollowing separation of said constituents from a biological sample, forexample, using electrophoresis. Detection can then be carried out inparticular using known immunofixation techniques, which require bringingreagents into contact with the constituents separated from the sampleand incubating them to produce an immunological recognition reaction ofthe constituents separated from the biological sample with the reagentsin predetermined zones of an analytical support.

[0004] The invention is advantageously used for routine analyses,particularly of the type carried out in the context of clinicalanalyses.

[0005] The invention also relates to a mask intended for depositing anddistributing one or more reagents on an analytical support, associatedin a device with positioning means that allow the mask to be positionedwith respect to the analytical support, in the proximity of saidsupport, when the mask is used to deposit and distribute the reagents.

[0006] These positioning means can also be associated with guide meansor can comprise guide means for displacing the mask when it ispositioned in the proximity of the analytical support, to allow thereagents to be distributed onto delimited zones of the support,including zones designated for incubation of the reagents with theconstituents of the sample.

[0007] The device of the invention allows reagents to be deposited ordistributed manually. It can also be arranged for automated depositionof these reagents and optionally for automated distribution.

[0008] In some embodiments of the invention, the step for loading thereagents into the mask can also be carried out manually or in anautomated manner. Advantageously, the mask of the invention is moreeasily loaded than available prior art masks.

[0009] In a further aspect, the invention provides a method fordepositing and distributing reagents on an analytical support.

[0010] In one particular implementation of the invention, the method isused to deposit and distribute reagents intended to carry outimmunofixation to detect and possibly quantify specific constituentscontained in a biological sample, said constituents having already beenseparated by electrophoresis on a support such as agarose gel.

[0011] The invention also concerns an immunofixation method employingsaid mask.

[0012] In a further aspect, the invention provides a kit comprising amask in accordance with the invention.

[0013] A kit in accordance with the invention is advantageously adaptedto carry out an immunofixation method using the mask of the invention.

[0014] The invention also concerns means for positioning and guiding themask.

[0015] It should be remembered that immunofixation, which can analysebiological samples with a view to typing the paraproteins they contain,is a widely practised routine analysis carried out in clinical analysislaboratories in particular.

[0016] That technique, which combines electrophoresis with the formationof precipitates on the electrophoresis gel, has been known for a longtime. The technique has in particular been described by Alper C A andJohnson A M Vox. Sang. 17: 445 (1969), Cawley L P et al., Clin. Chem.22: 1262 (1976), Ritchie R F and Smith R Clin. Chem. 22: 497, 1735, 1982(1976). It allows the identification of anomalies in differentbiological samples, in particular in biological liquids, for exampleserum, urine or cerebrospinal fluid.

[0017] The technique principally comprises the following steps:

[0018] 1) separating protein constituents from the test serum or liquidby electrophoresis on a support such as a gel, for example agarose gel;

[0019] 2) an immunological reaction with specific antibodies for theseparated proteins;

[0020] 3) revealing the immunological complexes formed.

[0021] The conditions for carrying out these steps have been describedin the prior art.

[0022] The devices used also comprise the possibility of producing areference lane (track) on the same electrophoresis support, inparticular on the same gel, obtained by fixing all of the separatedproteins present on the sample using a protein fixative including, forexample, a polyvalent antiserum.

[0023] New semi-automatic techniques for applying the biological samplesto be analysed, for migration under controlled temperature and fordepositing the reagents (including, for example, the antiserums andfixatives) allow immunofixation profiles to be miniaturised whilekeeping the sensitivities and resolutions satisfactory. Miniaturisationallows a larger number of samples to be analysed on the sameelectrophoresis support, in particular on the same gel.

[0024] Thus, in a few years we have advanced from carrying out one tocarrying out nine immunofixations on a single 8×10 cm electrophoresisgel (using, for example, an immunofixation kit sold by SEBIA under thetrademark Hydragel 9 IF). This saves time as regards the analysis andreduces reagent consumption, resulting in a reduction in analyticalcosts.

[0025] To deposit the reagents with a view to carrying outimmunofixation under such conditions, European patent EP-B1-0 526 271,for example, describes a mask or device for distributing reagents,generally specific antiserums and a fixative, that can overcome some ofthe problems posed by prior art devices or masks and that is safer andeasier to use. Thus, to carry out 9 immunofixations, for example, on thesame electrophoresis gel in three rows of three samples using the maskdescribed in EP-B1-0 0 526 271, for each sample, 6 reagents have to bepipetted out (fixative, anti-IgG antiserum, anti-IgA antiserum, anti-IgMantiserum, anti-k antiserum and anti-λ antiserum), i.e., a total of 54pipetting operations.

[0026] These manual pipetting operations can prove to be long anddifficult even if repetitive dosing pipettes are used.

[0027] The primary aim of the present invention is to improve theconditions for depositing and distributing reagents on an analyticalsupport using masks, by proposing a mask that can reduce the number ofreagent pipetting operations and which can reduce the quantity ofreagents used. The means proposed in the context of the invention can beused in any analytical technique requiring controlled deposition ofreagents on an analytical support. In this respect, the followingtechniques can be mentioned: immunofixation following electrophoreticseparation; or distribution onto a specific substrate for enzymaticdeveloping, for example for assaying lactodehydrogenase (LDH) orcreatine kinase (CK).

[0028] In a first aspect, the invention provides a mask for depositingand distributing reagents on an analytical support the design of whichtakes into account its use including its displacement to carry out thestep of distributing reagents onto predetermined zones on an analyticalsupport. The mask of the invention can therefore be considered to be amovable mask when in use.

[0029] The present invention also limits reagent consumption, inparticular that of antiserums, which are expensive products, andfixative in the case of immunofixation reactions, and can thus reducethe cost of the analyses carried out. It also facilitates loading thereagents into the mask, in particular by limiting the number ofpipetting operations and/or by enabling the mask to be loadedautomatically.

[0030] Further, the proposed mask ensures a consistent quality of theresult, under improved or even simplified manipulation conditions. Inparticular, after the phase for incubating the reagents distributedusing the device of the invention, it is no longer necessary toeliminate excess reagents that remain between the gel and the mask, asis the case when using a mask proposed in EP-B1-0 526 271

[0031] With the mask of the invention, after spreading and distributingthe reagents, no more free reagent is present between the mask andanalytical support, as all of the reagents that were initiallyintroduced have been deposited on the analytical support. Thus, it isnot necessary to pump off any excess reagents that may be present on theanalytical support.

[0032] Thus, the invention provides a mask for depositing anddistributing reagents on an analytical support for analysing biologicalsamples, comprising:

[0033] a lower surface and an upper surface that are at least partiallymutually parallel, separated by a distance constituting the thickness ofthe mask;

[0034] one or more delimited zones (lanes) located on the level of thelower surface of the mask and comprising an element that projects(projecting element) from the lower surface of the mask, each projectingelement comprising a portion constituting a slope with respect to ahorizontal plane;

[0035] associated with each lane, an opening traversing the mask overthe whole of its thickness from an upper orifice on the upper surface ofthe mask to a lower orifice, said lower orifice being located in thelane in the proximity of the lowest point of the slope of the lane; themask being such that the lane or lanes it comprises can hold reagentsloaded into each opening and deposited on the analytical support bycapillary action between the lane and the surface of the analyticalsupport facing which the mask is to be placed.

[0036] The expression “mask” as used in the present invention generallydesignates a plate designed to allow positioning in alignment withdelimited zones on an analytical support, if necessary in conjunctionwith associated means, in which reagents must be deposited anddistributed when they are loaded into the mask and brought into contactwith the delimited zones.

[0037] The dimensions of the mask of the invention are such that it doesnot cover the whole surface of the analytical support on which thereagents loaded on the mask are deposited and distributed, when the maskis brought in proximity of the analytical support, for operation. Thewidth of the mask (comprising the length of its lanes) is in particularinferior to the length of the electrophoretic migration lanes of theanalytical support, since the length of the lanes of the mask is smallerthan the length of the electrophoretic migration lanes of the analyticalsupport. The distribution of the reagents on these lanes results thusfrom the displacement of the mask above the analytical support asdisclosed hereafter, and from the moving of the reagents on said supportwhich is permitted as a consequence of the structure of the lanes of themask.

[0038] The mask of the invention is thus intended for displacement abovethe analytical support, in order to enable the distribution of thereagents.

[0039] The opening is stated to be “associated with each lane”, which inthe context of the present invention means that its lower orifice islocated so as to supply the reagent loaded into the opening in the maskto the slope of the lane, to allow the reagent to be deposited on theanalytical support and to hold it by capillary action between thesupport and the lane and to distribute it on the analytical supportduring displacement of the mask.

[0040] Said opening is, for example a hole, perpendicular to the uppersurface of the mask, traversing the mask from one side to the other. Thelower orifice of the opening is preferably located in the slope, in theproximity of the lowest point of the slope. By being located “in theproximity of” the lowest point—with respect to a horizontal plane—of theslope of the lane, the lower orifice of the opening enable to distributethe liquid reagent in the lane, as the reagent rises along the lane.

[0041] The upper orifice of the opening can be vertical to the lowerorifice. Alternatively, it can be positioned along an inclined planewith respect to this vertical provided that it allows the reagent to besupplied to the lower orifice under conditions compatible with thedeposit and distribution of this reagent on the analytical support.

[0042] Advantageously, an opening associated with a lane, constituted bya hole perpendicular to the upper surface of the mask and traversing itfrom side to side is formed by a circular orifice opening in the uppersurface of the mask, which is extended by a truncated conical portionending, for example, in a cylindrical portion opening into the lowersurface of the mask, via an orifice located in the slope of the lane inthe proximity of the lowest point of the slope. The presence of acylindrical portion opening into the lower orifice can distribute thepressure that can, for example, be exerted by a pipette on the edges ofthe lower orifice when loading the reagents, thus improving the strengthof the mask.

[0043] The truncated opening can also advantageously guide a fillerpipette and provide a seal between the end of the pipette and the maskwhen injecting the reagent between the lane and the analytical support.

[0044] If necessary, the above opening can be modified in that theconical portion extends to the upper orifice of the opening via acylindrical portion with a circular cross section.

[0045] According to a particular embodiment of the invention, theopening thus disclosed can also be such that the upper orifice is largerthan the lower orifice of the opening, for instance its diameter of theupper orifice is larger than the diameter of the lower orifice if theorifices are circular one.

[0046] A particular mask as defined above that is suitable fordistributing reagents on an analytical support for biological samplescan be defined as comprising:

[0047] a lower surface and an upper surface that are at least partiallymutually parallel, separated by a distance constituting the thickness ofthe mask;

[0048] one or more lanes each comprising a projecting element ofelongate shape emerging beneath the lower surface of the mask, saidprojecting element comprising a portion constituting a slope withrespect to a horizontal plane;

[0049] associated with each lane, an opening traversing the mask overthe whole of its thickness from an upper orifice on the upper surface ofthe mask to a lower orifice, said lower orifice being located in thelane in the proximity of the lowest point of the slope of the lane; themask being such that the lane or lanes it comprises can hold reagentsloaded into each opening and deposited on the analytical support bycapillary action between the lane and the surface of the analyticalsupport facing which the mask is to be placed.

[0050] The lanes of the mask are elongate in shape and can also betermed ramps. Their slopes are all inclined in the same direction.

[0051] Said slopes are intended to retain the reagents by capillaryaction as indicated above and to ensure that the reagent is brought atthe lowest point of the slope in order to permit its distribution whenthe mask is displaced.

[0052] A further particularly preferred mask of the invention as definedabove comprises:

[0053] a lower surface and an upper surface that are at least partiallymutually parallel, separated by a distance constituting the thickness ofthe mask;

[0054] one or more lanes each comprising a projecting element emergingbeneath the lower surface of the mask, constituted by a protuberance inthe shape of a truncated parallelepiped, said projecting elementcomprising a portion constituting a slope with respect to a horizontalplane;

[0055] associated with each lane, an opening traversing the mask overthe whole of its thickness from an upper orifice on the upper surface ofthe mask to a lower orifice, said lower orifice being located in thelane in the proximity of the lowest point of the slope of the lane; themask being such that the lane or lanes it comprises can hold reagentsloaded into each opening and deposited on the analytical support bycapillary action between the lane and the surface of the analyticalsupport facing which the mask is to be placed.

[0056] When the projecting element is constituted by an element with anelongate shape or is constituted by a protuberance in the shape of atruncated parallelepiped, said projecting element has an upper surfacecoinciding with the portion of the lower surface of the mask from whichit emerges, and a lower surface that is separate from the upper surfacealong at least one slope to the horizontal, the lowest point of saidslope located in the proximity of said lower orifice of the opening ofeach lane being the point that is closest to the analytical supportfacing it and in the proximity of which it is brought when in theposition of use.

[0057] The projecting element comprising a slope emerging from the lowerface of the mask can advantageously allow deposition and distribution ofreagents loaded into the mask by displacing the mask along a zone of theanalytical support that comes to face the lane or lanes of the mask in aplane that is horizontal with respect to this support.

[0058] In a further embodiment of the invention, the mask is providedwith one or more lanes each comprising a projecting element emergingbeneath its lower surface, said projecting element including a hollowsphere the cavity of which is intended to receive a reagent, and thedimensions of which are adapted to the width of the zone of theanalytical support that has to be covered by the reagent, said reagentbeing held in the sphere cavity by capillary action and distributed overthe analytical support as the mask is displaced, via a hole formed inthe sphere. Such a mask will also have the characteristics defined abovefor the projecting elements with an elongate shape.

[0059] In a particular embodiment of the invention, the lower and uppersurfaces of the mask are completely parallel to each other, away fromthe zones constituting the lanes, namely away from the zonesconstituting the slopes of the lanes.

[0060] In the context of the embodiments of the invention describedabove, the slope coincides with the lane at each lane of the maskregardless of the shape of the projecting element.

[0061] Alternatively, the slope can extend over only a portion of thelane. As an example, the lane comprising the lower orifice at the lowestpoint of its slope can be extended beyond said slope, for example in ahorizontal plane. In a further variation, the slope can be constitutedby a plurality of slopes.

[0062] When a mask in accordance with the invention is used inassociation with a support for analysing biological samples, for examplean electrophoresis gel, this mask is brought “into the proximity of” theanalytical support: this means that the mask does not come into contactwith the zones of the support onto which the reagents are to bedeposited and distributed (the reagent incubation zones) and that thereagent or reagents deposited on said support are held by capillaryaction between the lanes of the mask and said analytical support, whichallows them to be distributed over the predetermined zones of thisanalytical support located facing the lanes of the mask during itsdisplacement parallel to the analytical support, above that support. Theabove absence of contact is more specifically, in particular embodimentsof the invention, an absence of contact which follows the initiation ofthe descend of the reagents to allow their deposit on the analyticalsupport, this descent indeed involving, according to a particularembodiment of the invention, a brief contact with the analyticalsupport, as described and illustrated hereafter.

[0063] The slope formed at the projecting element of each mask lane issuch that its point said to be the lowest is the point that is closestto the horizontal plane constituted by the analytical support in theposition of use. As a result, the point termed the highest point of theslope of said lane is the point furthest from the horizontal planeconstituted by the analytical support in this operational position. Thelower face of each lane of the mask facing the support is thus inclinedwith respect to the horizontal.

[0064] During distribution of the reagents deposited on the analyticalsupport, the position of the lanes with respect to the horizontal planeof the analytical support and the position of the lower orifice of theopening associated with each lane ensures that the reagents reach thelowest point of the slope of the lane, as at that point, the capillaryforces exerted on the reagents are at their greatest.

[0065] The liquid constituting the reagent can be distributed over thewhole of the lane or over only a portion of the lane.

[0066] The reagent or reagents can be deposited or distributed using themask of the invention in a controlled manner over the delimited zones ofthe analytical support without establishing any contact between thelanes of the mask and the analytical support.

[0067] Away from the zones of the analytical support that come into linewith the lanes of the mask during use, contact can be establishedbetween the mask and the analytical support since on moving, the maskcan slide parallel to the analytical support along this support withoutdamaging it.

[0068] In one particular embodiment of the invention, no point of themask comes into contact with the analytical support during use, with thepossible exception of zones of the mask that allow it to be positionedin the proximity of the analytical support.

[0069] Preferably, when the mask has to be supported to position it inthe proximity of the analytical support, this is accomplished away fromsaid analytical support, for example on the plane (or plate) on whichthe support is deposited.

[0070] When considering the upper surface and the lower surface of themask, of the lanes or the slopes, these notions are considered to bemade with reference to the position of the mask above an analyticalsupport that is itself in the horizontal position. In other words, thelower surface of the mask and the lower surface of each lane or eachslope are facing the surface of the analytical support when the mask isin the position of use. The horizontal plane with respect to which theslope of the projecting element is defined can thus be that of theanalytical support when it is used in a horizontal position.

[0071] The invention also concerns a mask the use of which to depositand distribute reagents on an analytical support calls on the principleof the invention, namely holding the reagents by capillary actionbetween a slope defined in the mask and a zone of the analytical supportfacing said lane, said mask being distinguished from the mask definedabove in that the slope constituted in each lane of the mask is producedby the inclination conferred on the mask with respect to the analyticalsupport during its use. The lower surface of the mask in this case isparallel to the lower surface of the projecting element which comes toface the analytical support, the slope resulting from the inclinedposition of the mask with respect to the analytical support.

[0072] In the context of this particular embodiment, the characteristicsof the lanes defined for masks wherein the slope is integrated into thelane are transposable when the slope is constituted by using the mask inan inclined position with respect to the analytical support.

[0073] When the lane is elongate in shape, it can have aparallelepipedal shape, its shape delimiting the zone for holding thereagents by capillary action between the lane and the analyticalsupport. When in use, the opening traversing the mask is located at apoint on the lane that is in the proximity of the lowest point of theslope formed by the relative inclination of the mask with respect to theanalytical support.

[0074] The mask of the invention has dimensions that are compatible withthe dimensions of the analytical support on which the reagents are to bedeposited and distributed and the lanes of this mask have shapes anddimensions that are compatible with the volume of the liquid reagentthat is to be deposited and distributed on the analytical support andwith the shape and the dimensions of the delimited zones on theanalytical support on which said reagents are to be deposited anddistributed, for example with a view to their incubation with theconstituents of the biological sample.

[0075] To deposit and distribute one or more reagents on the biologicalsample analytical support when the mask and the analytical support aredisposed parallel to each other, the mask is displaced in a horizontalplane above the plane of the analytical support from the zone of theanalytical support at the level of which the mask is initiallypositioned and which corresponds to the initial deposition point of thereagents, to distribute the reagents on the zones of the analyticalsupport coming to face the lanes of the mask.

[0076] To deposit and distribute one or more reagents on the sampleanalytical support, when the slope of the lanes of the masks does notresult from the structure of the lanes but from the inclination endowedon the mask with respect to the analytical support (or vice versa), themask is displaced in a given inclined plane employing features that areidentical to those described for the mask in which the lanes comprise aslope in their structure.

[0077] Each displacement permitting passage of the mask above thetotality of the delimited zones of the analytical support that are toreceive the reagents is termed a “sweep”. A first sweep can, forexample, be carried out from the zone corresponding to the anode of anelectrophoresis support towards the zone corresponding to the cathode ofsuch a support, or in the opposite direction from the cathode to theanode, to cover the whole of the delimited zones that have to receivethe reagents, these zones corresponding to the electrophoretic migrationlanes in the case of an electrophoresis support (such as a gel). In thefollowing paragraphs, according to the above indications, when the anodeis referred to in order to locate the deposit of the reagent or themoving direction of the mask with respect to the analytical support, itmust be understood that this location or this movement can, opposite, beperformed starting from the cathode.

[0078] During its displacement by sweeping the predetermined surface ofthe analytical support after loading the reagents into the openingassociated with each lane, the mask of the invention can thus depositand distribute said reagents over the totality of the predeterminedzones on the analytical support for all of the test biological samplesfound in the direction of displacement of the mask.

[0079] Thus, it becomes unnecessary to multiply pipetting of eachreagent for each sample to be treated. The number of pipettingoperations to be carried out corresponds to the number of reagents thathave to be deposited over one row of the analytical support and thusnormally corresponds to the number of openings provided in the mask whenall of the lanes of the mask are used.

[0080] Further, the quantity of each reagent loaded into the mask can beconsiderably reduced compared with the quantity of each reagent normallyused when each reagent has to be loaded for each of the samples presenton the analytical support.

[0081] By way of example, if the mask of the invention is intended todeposit and distribute reagents to carry out immunofixation to detectparticular constituents of a biological sample that has already beenanalysed by electrophoresis, when using 6 reagents for each test sample(i.e., generally a fixative that is capable of fixing the constituentsof the sample to produce a reference profile on the electrophoresissupport, and specific anti-IgG, IgA, IgM, κ and λ antiserums), thequantity of each reagent loaded into the mask is reduced by 4.5 timescompared with the quantity loaded for each sample to be treated whenusing a fixed mask such as that described in EP-B1-0 526 271.

[0082] The quantity of each reagent loaded onto each lane of the mask isdetermined as a function of the dimensions of the incubation zone to becovered using this reagent, for example as a function of the number ofrows of samples found in the direction of displacement of the mask. Whenthe mask is used to deposit and distribute reagents for immunofixation,the incubation zone comprises or coincides with the zone of theelectrophoresis support that comprises the electrophoretic profile forthe samples to be analysed.

[0083] By way of example, a mask comprising three groups of six lanesover a row can be used to carry out immunofixation of nine samples, oreven 12 or 18 samples (distributed, for example, in rows of 3 differentsamples, each sample occupying 6 lanes of the analytical support forelectrophoresis and thus of the mask).

[0084] The mask is advantageously loaded with a quantity of reagentssuch that each predetermined zone on the analytical support on which thereagent has to be distributed is already homogeneously covered with thatreagent, in one sweep. To determine the loaded volume of each reagent,we take into account the path of the mask per sweep of the analyticalsupport and of the width of the zone to be covered on the analyticalsupport. Generally, the quantity of each loaded reagent varies between 4μl and 15 μl, and is a quantity of 15, 10, 8, 6 or 4 μl per reagent, forexample.

[0085] By way of example, we observe that a volume of 4 μl of reagent issufficient to cover an analytical support surface of 175 mm², in ahomogeneous manner, corresponding to a distribution of reagent of 0.02μl/mm² of analytical support.

[0086] Preferably, the mask of the invention is a rigid mask, orstiffened by association with stiffening means which can, for example,participate in positioning and/or guiding the mask.

[0087] The choice of material used to produce the mask is not limited inprinciple.

[0088] The mask can, for example, be produced from a material that canbe moulded to produce a smooth surface, in particular a plasticmaterial.

[0089] The material may be transparent or translucent; examples arematerials such as polycarbonate, polymethacrylate, polyethylene,crystalline polystyrene, and Plexiglas.

[0090] The mask of the invention can be disposable.

[0091] The stiffness conferred on the mask can allow it to be displacedin a predetermined plane, which may be horizontal or inclined, withrespect to the analytical support, when associated, for example snapfitted, into suitable positioning means and appropriate guide means.

[0092] In a preferred embodiment of the invention, a mask with thecharacteristics defined in the foregoing pages comprises a plurality ofmutually parallel lanes distributed over the length of the mask.

[0093] When, as is most frequently the case, the mask comprises aplurality of mutually parallel lanes, the distance between the lanes(inter-lane distance) is determined as a function of the number of laneson the mask, and the necessity of preventing any interactions betweenthe reagents, in particular between the fixative and the antiserums.

[0094] Advantageously, the distance between the different parallel lanesis constant. This distance can be small, for example less than 3 mm, inparticular of the order of 2.5 mm, preferably 2 mm or more, inparticular to prevent any interaction between the fixative and theantiserum of the neighboring lane.

[0095] The width of the zone of the analytical support at whichdistribution of each of the reagents has occurred is at least equal tothe width of the mask lane brought to face that zone.

[0096] By way of example, the width of the lane and the width of theincubation surface, which can correspond with the distribution of theelectrophoretic profile on the analytical support, are similar and about2.5 mm. In a further example, the width in question is 3.5 mm.

[0097] To prevent an interaction between neighboring reagents, it isalso possible to dispose the lanes of the mask to prevent overlapping ofthe different zones for depositing the reagents or of any possiblediffusion zones for the reagents deposited on the analytical support, orit is possible to to carry out the loading of the reagents and theirdescent on the analytical support in such a way that a possibleinteraction is prevented. Some embodiments to enable loading and descentof the reagents are described hereafter, including for example but notnecessarily, a loading step outside of the analytical support, whichpermits to avoid such type of interaction but permits to maintain thelanes parallel and aligned.

[0098] Regarding the above discusses interactions, it is appropriate inparticular, to ensure that the reagent intended for producing thereference profile for each sample does not interact with the specificreagents (in particular antiserums), which could falsify detection ofparticular constituents of the sample.

[0099] To this end, when specific means are present in the structure ofthe mask, a first embodiment of the mask comprising a plurality ofmutually parallel lanes distributed over the length of the mask with aconstant spacing consists of providing a first series of mutuallyparallel lanes distributed over the length of the mask and a secondseries of mutually parallel lanes that are parallel to the first seriesof lanes and wherein the lower orifices are located in the samehorizontal plane, this second series of lanes forming an alignment thatis offset with respect to the alignment formed by the first series oflanes.

[0100] In a variation of the mask, the offset alignment of the secondseries of lanes is replaced by increasing the spacing between said lanesof said first series and the other lanes of said second series.

[0101] The offset of the second series of lanes or the spacing of thisseries of lanes compared with the lanes of the first series is intendedto prevent interaction between the reagents of the second series oflanes and those of the other lanes during deposition onto the analyticalsupport. In general, these offset lanes or more spaced lanes areintended to receive a fixative for immunofixation, capable of fixingproteins of the electrophoretic profile to produce a reference profile.

[0102] When the mask does not contain a series of offset lanes or aseries having a different spacing compared with that of the other lanes,the interaction between the reagents in question can be avoided, ifnecessary and for example, by carrying out loading and deposition ofthese reagents onto the analytical support separately in two sweeps.

[0103] As an example, the fixative is deposited on the anode side of theelectrophoresis support, then distributed by sweeping before loadingwith the antiserums, for example in the anodic but offset position, forexample about 5 mm further towards the cathode with respect to theposition of the first loading run. Alternatively, the antiserums can beloaded onto the cathode position.

[0104] Having recourse to a two-stage loading is however not alwaysrequired, especially when the loading procedure of the reagent does notlead to a disturbing interaction between the reagents. Such interactioncan, for example, be prevented even if all the reagents are loadedsimultaneously outside of the surface of the analytical support and whenthe simultaneous descent of all the reagents can be performed on theanalytical support without creating a disturbing interaction.

[0105] When the mask is produced so that the slope of the lanes resultsfrom the inclination of the mask with respect to the analytical supportand not from the structure of the lanes, the offset of the lanes orgroups of lanes is not necessary, and the reagents can then be loadedand deposited in several stages depending on their nature.

[0106] The mask of the invention can be produced so that the lanes areorganised into a plurality of groups, each group, for example, beingconstituted by a lane positioned in an offset manner with respect to theother lanes aligned with respect to each other, and by the aligned lanespreceding the next offset lane.

[0107] Further, the mask of the invention is such that its structure,and if necessary the conditions of its use, allow the deposition anddistribution of the reagents without interaction between the differentreagents deposited on the different zones of the analytical support.

[0108] In particular for the zone for initial deposit of the reagentsonto the analytical support, it has been observed that prior to theirdistribution, there is a localised diffusion phenomenon of said reagentson the analytical support.

[0109] To avoid any consequences of localised diffusion phenomenaregarding the reagents on their deposition, it is advantageous to chooseto deposit reagents with a mask away from the zone of the analyticalsupport that is susceptible of carrying the constituents of the samplesto be detected, thus for example away from the zone comprising theelectrophoretic profiles.

[0110] In the case of immunofixation, said reagents are, for example,deposited in a zone located away from that corresponding to theelectrophoretic profile, for example on the anode side of the supportwith respect to these profiles.

[0111] Advantageously, the mask of the invention is such that theopening traversing it from one side to the other is perpendicular to theupper and lower surfaces of the mask.

[0112] The shape of the openings of the mask must allow a sufficientquantity of reagents to be deposited therein to allow deposition anddistribution of this reagent over the whole of the predetermined zone ofthe analytical support without having to reload the mask with saidreagent.

[0113] Further, the shape and location of this opening is compatiblewith depositing and holding by capillary action a given quantity ofreagent between the lane of the mask and the analytical support, untilthe quantity introduced during the operation for distributing thereagent on the analytical support is exhausted.

[0114] When depositing reagents on the analytical support, when the maskis loaded above the analytical support with the filling of the lanesbeing carried out as the reagents are loaded, it is appropriate toprovide a seal between the mask and the end of the pipette or any othermeans used to load the reagents into the mask.

[0115] The volume of the opening can be designed to allow loading of thereagents externally of the analytical support, the reagents in this casehaving to be retained by capillary action in the opening in theirentirety, until they are deposited on the analytical support. In thiscase, the mask is then positioned to ensure deposition of the reagentsit contains, on the analytical support. This positioning must thusensure that contact is established between the liquid and the analyticalsupport, possibly using particular features.

[0116] Advantageously, in each lane, the opening can receive the excessreagent over the quantity of reagent required for the reaction.

[0117] The mask of the invention can employ reduced quantities ofreagents, for example about 15 μl or 10 μl. However, the dimensions ofthe opening traversing the mask and intended to receive these reagentscan be determined to allow a quantity of reagents that is higher thanthe effective quantity employed to be accepted. As an example, thevolume of the opening can accept a quantity of reagent of up to about 30μl.

[0118] The geometrical characteristics of the mask, in particular thenumber of lanes and the distance between the lanes (inter-lane distance)are adapted to the number of deposits, to their width and to the spacingof these deposits, formed in rows on the analytical support. The mask ofthe invention has thus a sufficient length to comprise several lanesformed in a row, and a limited width (smaller) with respect to thelength of the electrophoretic migration lane of the incubation surfaceof the analytical support facing this lane when the mask is displacedwhen orperated.

[0119] It is understood, and this constitutes a characteristic of thepresent device, that the same mask can be used to produce a plurality ofrows of deposits with the same number and dimensional characteristics onthe same gel. These rows of deposits have been produced on theanalytical support in rows that are mutually parallel, and perpendicularto the direction of electrophoretic migration.

[0120] Advantageously, the geometry of the mask of the invention allowsdeposition and holds the reagent by capillary action between each laneof the mask and the analytical support, when the distance between themask and the analytical support is 2 mm or less, preferably in the range0.1 to 1.5 mm. This distance between the mask and the analytical supportvaries depending on the point on the mask under consideration; inparticular, this distance is preferably about 0.1 to 0.5 mm at the pointon the mask that is closest to the support (corresponding to the lowestpoint on the slope of the lane or the slope of the mask) and thisdistance is preferably less than 2 mm, advantageously less than 1.5 mmor less, at the point on the mask that is furthest from the analyticalsupport (corresponding to the highest point of the slope of the lane orthe slope of the mask).

[0121] Within these limits, the inclination of the slope must be suchthat the spacing of the mask from the analytical support is compatiblewith the capillary forces that maintain the reagent between the lane andthe analytical support.

[0122] By way of example, a mask of the invention is produced so thatthe lanes are separated from each other by a distance of 1.5 mm or more.Preferably, the distance between the lanes is 2.5 mm. The lane width isadvantageously 2.5 mm.

[0123] The mask lane reserved for the fixative can also be offset; forexample, it can be in a position that is closer to the anode than theother lanes, when the mask is in the position of use, in the proximityof an analytical support constituted by an electrophoresis gel.

[0124] A particular mask is characterized in that the lane intended forfixative is not aligned with the other lanes and is offset compared withthe alignment formed by the others, by a distance of 5 mm, preferably 6to 7 mm.

[0125] A particular mask that is suitable for the invention, and inparticular a mask that is suitable for use with a 10 cm longelectrophoresis gel and with a width (between the anode and cathodepoles) of about 8 cm is such that each lane of the mask has thefollowing dimensions:

[0126] length: 3 to 15 mm;

[0127] width: 1 to 10 mm;

[0128] inclination of the slope: 1° to 10° to the horizontal.

[0129] A particularly preferred mask that is suitable for use with theabove gel is a mask in which each lane has the following dimensions:

[0130] length: 7 mm;

[0131] width: 2.5 mm;

[0132] inclination of the slope: 5° to the horizontal.

[0133] In these particular embodiments, the other characteristics of themask described above can, naturally, be associated with the particularcharacteristics given above. In particular, the inter-lane distance isadvantageously 2.5 mm and/or the offset between the alignment of thelanes for the specific reagents and the alignment of the lanes for thefixative is 6 to 7 mm.

[0134] Again, in a particularly advantageous embodiment of theinvention, the mask is such that the opening that traverses it havingthe characteristics given above in that regard has a conical portionforming an angle of about 50°.

[0135] In the context of the different embodiments of the invention, thethickness of the mask is advantageously in the range 1 to 10 mm.

[0136] When the mask of the invention is used to deposit and distributethe reagents on the electrophoresis support, it can again becharacterized in that it is compatible with the characteristics oflocalisation of the biological samples separated on the electrophoresissupport; in particular, said mask can:

[0137] align the rows of lanes on the mask, perpendicular to thedirection of electrophoretic migration;

[0138] position the mask in the proximity of the analytical support, tohold the reagents by capillary action between the lanes of the mask andthe analytical support;

[0139] position the mask transversely with respect to the direction ofelectrophoretic migration to allow the alignment of the rows of theelectrophoretic migration carried out on the analytical support with therows of the mask lanes.

[0140] For use with different analytical supports, and by way ofexample, a mask in accordance with the invention can comprise in therange 1 to 24 lanes, preferably in the range 6 to 24 lanes, inparticular 6, 9, 12, 15 or 18 lanes.

[0141] If intended for use in an immunofixation reaction followingelectrophoretic separation, a mask comprising 18 lanes can deposit, forthree different samples occupying the same row of the electrophoresissupport, and for a given number of rows of samples (for example 2 ormore, in particular 3 or 4), a fixative to produce a reference profileand 5 specific reagents such as antiserums, in particular anti-IgG,anti-IgA, anti-IgM, anti-κ and anti-λ, for each sample. It is alsopossible to produce a mask with 6 or 12 lanes using the same features.

[0142] The invention also concerns a mask as defined above, associatedwith positioning means intended to hold the lower surface of the lanesof the mask in the proximity of the surface of the analytical supportclose to which the mask will be brought to deposit and distribute thereagents on the analytical support.

[0143] Suitable positioning means can be constituted by abutments thatcan rest on the analytical support away from the incubation surfacecomprising the biological samples, the dimensions of these abutmentsbeing such that the mask does not come into contact with the analyticalsupport over its portion corresponding to the incubation surface of thereagents.

[0144] The positioning means can also be associated with means forguiding the mask to allow it to be displaced in a controlled mannerabove the analytical support, in accordance with the foregoing.

[0145] Thus, in a further aspect, the invention provides a device fordepositing and distributing one or more reagents on an analyticalsupport for biological samples, comprising:

[0146] a) a mask as defined above;

[0147] b) means for positioning and guiding the mask allowing the maskto be positioned so that the mask is held in the proximity of thesurface of the analytical support and allowing the mask to be guided bysweeping the surface of the analytical support, in a horizontal planeparallel to the surface of said support, to allow to deposit anddistribute the reagents over each of the determined zones of theanalytical support coming into line with the lanes of the mask.

[0148] In a variation of the invention, the mask used is such that theslope of the lanes results from the inclination of the mask with respectto the analytical support. In this case, the invention provides a devicefor depositing and distributing one or more reagents on an analyticalsupport for biological samples, comprising:

[0149] a) a mask as defined above;

[0150] b) means for positioning and guiding the mask allowing the maskto be positioned so that the mask is held in the proximity of thesurface of the analytical support and allowing the mask to be guided bysweeping the surface of the analytical support, in a determined planeinclined to the surface of said support, to allow to deposit anddistribute the reagents over each of the determined zones of theanalytical support coming into line with the lanes of the mask.

[0151] In a particular embodiment of the invention, the device definedabove is such that the means for positioning and guiding the mask canestablish a distance between the analytical support and the point on themask that is closest to said support (corresponding to the lowest pointof the slope) that is in the range 0.1 mm to 0.5 mm, and a distance ofless than 2 mm, preferably 1.5 mm or less, from the point furthest fromthe mask and the support (corresponding to the highest point of theslope).

[0152] The distance between the analytical support and the point on themask that is closest to said support is preferably 0.5 mm.

[0153] The means for positioning and guiding the mask of the inventioncan be any suitable means, if appropriate present in an electrophoresisinstrument. A course limiter can, for example, be an abutment.

[0154] The guide means advantageously comprise a course limiter todelimit the mask displacement course.

[0155] In one particular embodiment of the invention, the positioningand guiding means can allow automated displacement of the mask along theanalytical support. However, the mask of the invention can readily bemanually displaced, to cover the whole of the determined zones on theanalytical support with the reagents contained in the mask by sweeping,if appropriate by means of a plurality of outward-and-returndisplacements.

[0156] The invention also concerns a method for depositing anddistributing one or more reagents on an analytical support comprisingbiological samples, the method comprising the steps of:

[0157] positioning a mask as hereinbefore defined or a device as definedabove in the proximity of the analytical support;

[0158] loading the reagent or reagents onto the mask to deposit thereagent or reagents onto the analytical support, holding them betweensaid support and the lanes of said mask by capillary action;

[0159] displacing the mask by sweeping the analytical support to allowdistribution of the reagent or reagents on the analytical support intothe delimited zones of said support, the reagent or reagents beingdistributed in a quantity sufficient to allow their interaction with theconstituents of the biological samples present on said analyticalsupport.

[0160] When the lanes of the mask comprise a sloped portion, the mask isdisplaced in a horizontal plane with respect to the plane of theanalytical support above the support and parallel to the support.

[0161] When the lanes of the mask do not comprise a slope and aretherefore positioned in an inclined manner with respect to theanalytical support to produce the slope, the mask is displaced parallelto the plane of the analytical support that is itself in the horizontalposition if the mask is inclined.

[0162] When the mask is positioned in the proximity of the analyticalsupport, and as soon as the reagents come into contact with theanalytical support, it can be displaced immediately by sweeping abovesaid analytical support.

[0163] When the reagents are distributed over the determined zones ofthe analytical support, for example over zones corresponding to theelectrophoretic migration lanes of the biological samples, these zonesconstitute the incubation zones for said reagents with the constituentsof the samples.

[0164] One advantage of using the mask of the invention lies in the factthat when distribution is terminated, the mask can immediately beremoved from the delimited zones constituting the incubation zones ofthe analytical support, the quantity of reagent loaded into the maskhaving been exhausted.

[0165] One further advantage linked to the use of the mask of theinvention is to allow uniform distribution of the reagents over theincubation zones.

[0166] Advantageously, an excess quantity of reagent is used withrespect to the quantity required to cover the zones of the analyticalsupport where incubation between the constituents of the samples and thereagents takes place. An excess of reagent is a quantity more than thatdistributed by a single passage (one sweep) at a sweep rate over theanalytical support of about 2 cm/s.

[0167] The quantity of reagent left on the analytical support per unitarea of swept surface depends on the surface area and in particular onthe sweep length. It rises as the sweep rate reduces.

[0168] The rate of displacement of the mask with respect to theanalytical support is normally in the range 0.5 to 2 cm/s.

[0169] By way of example, to distribute the reagents on anelectrophoresis support with a width of 8 cm determined between theanode and cathode (corresponding to the sweep length), two displacementseach comprising an outward and a return trip can be carried out, eachdisplacement taking about 3 seconds. In this case, a quantity of reagentper lane in the range 6 μl to 10 μl can be deposited.

[0170] At slow rates, i.e., at about 0.5 cm/s, and for a lane width of2.5 mm, a reagent in a quantity of 3-4 μl introduced beneath the lanewill be exhausted after a path of 70 mm.

[0171] For 2.5 mm wide lanes and with a sweep path for the mask of 70 mmcompared with the analytical support, the volume of reagentadvantageously employed is about 8 to 10 μl/lane.

[0172] When the first sweep has been carried out, some reagent is leftunder the lane even if the displacement is slow, at 0.5 cm/s, andespecially if the displacement is at an average rate of 2 cm/s.

[0173] Other sweeps will be necessary to completely exhaust the reagentsintroduced. The number of sweeps can vary as a function of the volume ofreagent introduced into each lane.

[0174] In practice, the volume of each reagent employed is such that 4sweeps are sufficient to exhaust the reagent.

[0175] With 10 μl loaded into each opening, the mask then, for example,undergoes 2 outward and return trips for a sweep length of 70 mm. Onceall of the reagents have been distributed onto the surface after these 4passes, the mask is withdrawn with no risk of unintentional distributionand the incubation phase proper is commenced.

[0176] According to a particular embodiment of the invention, two sweeps(one XXX outward-and-return displacement) to distribute the reagents onthe analytical support. Even if after the sweeps, a small quantity ofreagent remains on the analytical support, it is not necessary to removeit before incubation. The operating conditions of the mask enable auniform distribution.

[0177] If the sweep length is reduced, the quantity of reagentdistributed per lane is advantageously reduced.

[0178] We indicated above that the mask used to carry out the method fordepositing and distributing one or more reagents on an analyticalsupport is advantageously a mask in which the lanes intended for thefixative capable of fixing the constituents of the biological samples toproduce a reference profile are offset with respect to the other lanes,as described above.

[0179] This offset between the fixative lane and, for example, the lanesintended for the specific antiserums, avoids an interaction between thereagents when being deposited on the analytical support. This offset isparticularly justified when all of the reagents are loaded onto the maskand deposited together.

[0180] Alternatively, for example when the lanes intended for thefixative are not offset, the mask is loaded in two runs, to depositfirstly antiserums and then the fixative. This two-step loading canalternatively be carried out by initially loading and depositing thefixative then loading and depositing the specific reagents.

[0181] Alternatively also, the loading can be carried out in one step,if the conditions for the deposit of the reagents on the analyticalsupport are such that they do not lead to interactions between thereagents, in particular between the specific reagents and the fixativeif any.

[0182] When the mask is such that it has to be used in an inclinedposition to produce the slope in the lanes compared with the analyticalsupport, the lanes are not offset from each other, but loading ofreagents which must not be allowed to interact (for example, fixativeand antiserums) is carried out in either in two stages: the initiallyloaded reagent is distributed by sweeping prior to loading the reagent(for example antiserum) loaded in a second stage, or in conditionsallowing to avoid disturbing interactions when depositing the reagentson the analytical support.

[0183] In a particular implementation, the deposition and distributionmethod of the invention is carried out so as to load the mask with thereagents away from the zone of the surface of the analytical supportcomprising the biological samples.

[0184] When carrying out this loading, which takes a certain amount oftime (30 seconds to 2 minutes), the zone of the analytical supportcovered by the reagents at this location is wider than the lane itselfas a result of diffusion. This diffusion could cause abnormalenlargement of the profile, revealed after incubation of the reagentwith the constituents of the biological sample, should this loading becarried out vertically to a zone comprising a profile of theconstituents of the samples that are to be revealed.

[0185] If the mask is loaded away from the zones of the analyticalsupport comprising the constituents of the samples, this disadvantageresulting from diffusion of the reagents from the deposition zone doesnot occur.

[0186] When the size of the surface of the analytical support allows it,said loading can be carried out in the anode portion beyond the zone inwhich the electrophoretic migration profiles for said samples arelocated. The loading can alternatively be carried out in the cathodeportion beyond the zone in which the electrophoretic migration profilesfor said samples.

[0187] When the size of the surface of the analytical support does notallow such deposition beyond the zone containing the sampleelectrophoretic migration profiles, the mask can be loaded outside thesupport surface, for example onto a thin sheet of plastic, this sheetcoming into contact with the analytical support and in the plane of thesurface of this support but extending beyond this surface.

[0188] The invention also concerns a method for depositing anddistributing one or more reagents on an analytical support comprisingbiological samples, the method comprising the steps of:

[0189] loading the reagent or reagents onto the mask to allow thereagent or reagents to be deposited on the analytical support, and beingheld between said support and the lane or lanes of said mask bycapillary action;

[0190] positioning a mask as hereinbefore defined or a device ashereinbefore defined in the proximity of the analytical support;

[0191] displacing the mask by sweeping the analytical support todistribute the reagent or reagents on the analytical support indelimited zones on said support, the reagent or reagents beingdistributed in a quantity sufficient to allow them to interact with theconstituents of the biological samples present on said analyticalsupport.

[0192] The features indicated above for carrying out the deposition anddistribution method are applicable in this instance.

[0193] In this implementation of the mobile mask loaded prior topositioning it above the analytical support, all of the reagents havebeen introduced into the upper orifices of the openings associated witheach lane of the mask, which then act as reservoirs. These reagents areheld in them due to capillary action despite the presence of a lowerorifice for each opening.

[0194] In the configurations described above, when the mask is loadedabove the analytical support, the mask already having been placed at therequired distance (about 0.5 mm for the lowest point) from said support,the reagents are introduced directly between the lanes of the mask andthe analytical support.

[0195] To this end, during the phase for expelling the reagent that hasbeen held in the tip of the pipette, a seal is provided between the endof this tip and the upper orifice of the mask, for example by holdingthe pipette in the vertical position with the tip bearing lightlyagainst the bottom of the opening in the mask in the conical portionclose to the lower orifice of the opening. When this lower conicalportion is extended by a cylindrical portion, the diameter of thislatter (for example 0.8 mm) does not allow passage of the pipette tip.This ensures “forced” expulsion of the reagent via the lower orifice ofthe opening associated with the lane, the droplet that beads out fromthis lower orifice coming into contact with the analytical supportlocated in its proximity (0.5 mm) and distributing itself by capillaryaction between the lane and the support. When the pipette tip/upperorifice seal is not obtained, the reagent remains in the upper orificeand does not descend onto the analytical support.

[0196] This is precisely the case when the seal is provided but when thelower orifice is not in the proximity of the analytical support surface,i.e., when loading is carried out away from the analytical support.

[0197] Under these conditions, the droplet that has beaded out (but hasnot fallen because of its very small volume of 10 to 15 μl) and hasremained attached by capillary action close to the lower orifice, risesinto the well constituted by the upper orifice when the “tip/upperorifice contact” is destroyed by removing the pipette.

[0198] This particular implementation of the mask with loading prior topositioning it above the analytical support has the advantage of beingcapable of being carried out automatically, for example by means of theHydraplus SEBIA automated instrument, removing the need for any manualpipetting and further simplifying loading of the mask.

[0199] The mask loaded with reagents distributed in the upper orificesacting as a reservoir can be kept in a moist chamber for a period of afew minutes to a few hours prior to use.

[0200] Different means can be envisaged for bringing the reagents loadedinto the mask into deposition on the analytical support.

[0201] In a first embodiment, the mask and mask holder assembly (themask holder constituting a means for positioning the mask) loaded withdifferent reagents is positioned above the analytical support byattaching it to a guide rail and bringing it into abutment in the anodeposition. The mask assembly is covered with a small chamber (FIG. 3)covering all of the upper orifices and bearing on the periphery of themask (a planar surface sealing against a planar surface). This chamberis provided with a fitting via which a small volume of air, 50 to 200μl, is rapidly injected (for example using a syringe). This increase inpressure in the sealed chamber causes each of the reagents to bead outbelow the mask lanes and these reagents then touch the gel. Followingthis contact with the analytical support, they are simultaneouslydistributed between the lanes of the mask and the analytical support bycapillary action. The surface of the analytical support is then swept.

[0202] In a further embodiment, the mask and mask holder assembly thathas already been loaded is positioned above the analytical support byattaching the mask holder to the guide rail and is brought into abutmentin the anode position.

[0203] The reagents can be caused to fall onto the analytical supportfrom the upper orifices of the mask that act as a reservoir byintroducing, vertically into each of the upper orifices, a cylindricalrod with a diameter that is lower than that of the lower orifice of themask (for example 0.5 mm) constituted by a material with a hydrophilicnature (for example stainless steel) until the rod comes into contactwith the analytical support.

[0204] This rod can establish a junction between the liquid introducedinto the upper orifice and the analytical support. All of the liquidintroduced then descends by capillary action along the rod anddistributes itself between the lane and the analytical support.

[0205] The simultaneous descent of all of the reagents onto theanalytical support can be achieved by introducing a rod into each of theupper orifices of the mask vertically and simultaneously, these rods ofthe same length (5 to 10 mm) being rendered integral with each other,for example by insertion into a rectangular Plexiglas plate with thesame dimensions as the mask and with a geometry such that it exactlyreproduces the disposition of the orifices of the mask. When all of thereagents have been distributed between the lanes of the mask and theanalytical support, the Plexiglas plate provided with the rods iswithdrawn and the mask is swept across the gel surface.

[0206] In a further implementation of the invention, a third method thatallows all of the reagents to be dropped simultaneously onto the gelconsists of providing it with a mechanical impulse, after positioningthe mask in abutment (especially in anodic or in cathodic abutment)above the analytical support. This impulse can, for example, be obtainedby snap fitting the loaded mask into the mask support.

[0207] This impulse can project a drop of reagent, until then held bycapillary action in the reservoir of the mask, onto the analyticalsupport by inertia, and thus establishes a junction between the lowestpoint of the mask lanes at the lower orifice of the lanes and theanalytical support so that all of the reagents located in the reservoirsare distributed by capillary action between the mask lanes and theanalytical support. The gel surface can then be swept.

[0208] In a still further implementation, when the mask is loaded awayfrom the analytical support, after distributing the reagents into theupper orifices and installing the mask above the analytical support, themask is briefly brought into contact with the analytical support at thelowest point of the slope of the lanes. The purpose of such contact isto allow all of the reagents to fall onto the analytical support beforedistribution is commenced.

[0209] Once the loaded mask is in the position of use in one of theabove implementations, i.e., when each lane has received a predeterminedquantity of reagent, the mask is displaced parallel to the analyticalsupport in the direction of electrophoretic migration, using guidemeans. The result of this displacement is to entrain the liquid locatedbetween the lanes of the mask and the analytical support by sweeping thesurface of the analytical support coming into line with the lanes of themask. The liquid held between the mask and the analytical support bycapillary action is entrained in particular due to the slope of thelanes which enable that the reagent be brought at its lowest pointduring the displacement and a certain quantity of reagent is thendeposited on the analytical support into which it penetrates andremains. As sweeping progresses, the volume of liquid contained beneaththe lane is consumed by penetration into the analytical support andreduces.

[0210] The invention also concerns a method for depositing anddistributing reagents on an analytical support, in which the step forloading the mask with the reagent or reagents is automated.

[0211] In a further implementation of the invention, the step fordisplacing the mask for sweeping the analytical support is automated.

[0212] The method of the invention is advantageously carried out todetect biological sample constituents, previously separated byelectrophoretic migration, this detection possibly involvingimmunofixation, the reagents in this case being specific antiserums andpreferably a fixative to produce a reference electrophoretic profile.

[0213] Such a method of the invention can be carried out under the usualconditions for carrying out electrophoresis and immunofixationtechniques. The reagents used are the usual reagents, but these reagentsare advantageously being used in a quantity that is lower in theinvention compared with the quantities normally employed.

[0214] The invention also provides a method for detecting theconstituents of one or more biological samples by immunofixation,comprising:

[0215] carrying out electrophoresis of the biological sample or samplesto separate out the constituents;

[0216] carrying out a method for depositing and distributing reagents onan electrophoresis support, preferably an agarose gel, in accordancewith the invention;

[0217] incubating the biological samples separated by electrophoresiswith the distributed reagent or reagents to allow immunofixation.

[0218] Such a detection method can also be characterized in that itfurther comprises a step for revealing the constituents of immunofixedbiological samples and if appropriate, a step for quantifying therevealed constituents.

[0219] These revealing and quantification steps can be carried out usingany known means.

[0220] Advantageously, in the context of the invention, the methodsdefined above can simultaneously analyse 3n, 2n or n biological samplesrespectively, n being a whole number representing the number of rows ofdeposits, using a mask with 18, 12 or 6 analytical lanes respectively.Preferably, n is 2, 3 or 4.

[0221] However, in principle, there is no limit to the number of laneson the mask.

[0222] Because of the structure of the mask and the features of its use,the quantity of each reagent loaded onto each lane of the mask, i.e.,introduced into each opening of each lane and held by capillary actionbeneath each lane, can advantageously be reduced, and is, for example,less than 15 μl/lane. Preferably, the quantity is 10 μl/lane or less.

[0223] When the reagents are deposited on the analytical support, theyare in the liquid form. Thus, the invention concerns the use of liquidreagents to load the mask. The invention also concerns the use of a maskloaded with liquid reagents, the mask then being freeze dried so thatthe reagents contained in the openings of the mask are freeze drieduntil the mask is used when the reagents are in the form of solutionsfor the deposition step.

[0224] In a further aspect, the invention provides a kit comprising:

[0225] at least one mask as defined above;

[0226] at least one analytical support, in particular an electrophoresissupport.

[0227] Such a kit can also comprise:

[0228] reagents for immunofixation of the constituents of samplesseparated by electrophoresis;

[0229] a fixative for fixing each sample of the ensemble of constituentsseparated by electrophoresis.

[0230] The kit can also comprise at least one comb for depositingsamples on the analytical support.

[0231] If the mask has to be loaded away from the electrophoresissupport, the kit can comprise means, for example as described above, tocause the reagents to fall from the openings in the mask onto theanalytical support.

[0232] Such a kit is preferably suitable for simultaneous separation of9 or even 12 samples on each electrophoresis support, using a mask with18 lanes.

[0233] Preferably, such a kit can allow simultaneous separation of 18samples on each electrophoresis support.

[0234] A kit in accordance with the invention can also containindications relating to the use of the mask of the invention, forexample in the form of instructions for use including informationregarding the quantities of reagents to be loaded onto the mask and/oron the conditions for displacing the mask, such as the sweep rate or therecommended number of sweeps.

[0235] If need be, according to a particular embodiment of the kit ofthe invention, the mask is not with the analytical support which can beobtained independently.

[0236] The mask of the invention can advantageously be loaded with thereagents.

[0237] Further, the invention concerns an electrophoresis support forseparating at least 9 biological samples disposed in 3 rows of 3samples, for immunofixation, said support comprising at least 18migration lanes, said lanes being spaced from each other by a distanceof 2 mm and being 3 mm wide, and the total length of the migration lanesbeing at most 63 mm.

[0238] Other characteristics, advantages and details of the inventionwill become apparent from the following description, made with referenceto the accompanying drawings, in which:

[0239]FIG. 1 is a diagrammatic perspective view from below of a maskholder device of the invention;

[0240]FIG. 2 is a diagrammatic perspective top view of this device;

[0241]FIG. 3 is a diagrammatic perspective top view of this device andits associated cover;

[0242]FIGS. 4 and 5 are views from below and the side respectively ofthe mask of the invention;

[0243]FIG. 6 is a cross sectional view along line VI-VI of FIG. 4;

[0244]FIGS. 7 and 8 are diagrammatic perspective views of twovariations;

[0245] FIGS. 9 to 17 illustrate another embodiment of the inventionwhere the lanes are formed in one row only.

[0246]FIG. 9: top view of the guide permitting to position the maskabove the electrophoresis support and to displace the mask above thesupport (gel) in a given direction and on a given stoke;

[0247]FIG. 10: Top and bottom views of the carriage which is mounted onthe rail 14 by means of a slide 49. The carriage has four feet 30 whichare applied on a plane in which the electrophoresis gel is positioned,on either side of the gel. The feet 30 may slide on this plane.

[0248]FIG. 11: Top and bottom views of the mask holder which receivesand maintains the mask by means of notches 43 and springs 28. The maskholder comprises a bearing zone 46 on which a pressure is applied tomove the mask into contact with the gel.

[0249]FIG. 12: assembly of a carriage and a mask holder which areconnected by two spring leaves 47 maintained by rivets 48. Thisassembly, when monted on the guide rail 14 by the slide 49, permits tomaintain the mask parallel to the gel and at the vicinity of the gelwithout contact.

[0250] In order that the reagents loaded in the mask wells may descent,a pressure is applied on the mask holder. This causes a bending of thespring leaves 47 and the lowest part of the lanes, where the lowerorifice of the filling conduits 34 is situated, comes into contact withthe gel (an abutment system permits to limit the bending in order not todamage the gel).

[0251] By releasing the pressure at the bearing zone 46, the mask isallowed to move up and returns to its initial position and the reagentscontained in the conduits 36 are distributed by capillarity between thelower part of the lanes and the gel.

[0252] The mask is then moved forth and back by means of the handle 26.

[0253]FIG. 13: Top view of the assembly comprising the carriage, themask holder and the mask.

[0254] FIGS. 14 to 17: represent the mask and guide assembly mounted onthe positioning bar 50 on the electrophoresis plate in its end sweeppositions.

[0255] The device shown in FIGS. 1 to 3 comprises a mask 10 inaccordance with the invention, removably mounted on a support arm 12,substantially in the shape of a C, which is attached to and guided intranslation on a rail 14 of a slide 16 for positioning and fixing on aplate (not shown) that carries the analytical support (for exampleagarose gel).

[0256] Slide 16 extends over one edge of this plate parallel to thedirection of electrophoretic migration and comprises two transverseslots 18 in which are engaged hollow pins 20 carried by a further slide21 that is integral with the edge of the plate, the hollows in pins 20nesting into dogs emerging from the migration plate (not shown) andassociated with screws 22 for adjusting the transverse position of slide16 and thus of mask 10 with respect to the plate and analytical support.This slide also includes screws 24 that can lock the slide afteradjustment.

[0257] Rail 14 extends parallel to the direction of electrophoreticmigration and is engaged in a corresponding groove at one end of arm 16.This end carries a handle or rod 26 for translational displacement onrail 14 in one direction or the other.

[0258] In a variation, motorised means can be provided on slide 16 forautomated displacement of arm 12, for example an electrical motor thedrive shaft of which bears on a toothed wheel or pulley co-operatingwith a chain or belt respectively, connected to arm 12.

[0259] Mask 10 is fixed to arm 12 using any suitable means, for examplean elastic snap fit as shown at 28, and is formed by a flat elongatesubstantially rectangular plate that extends transversely, i.e.,perpendicular to the direction of electrophoretic migration.

[0260] This plate is held above the analytical support at apredetermined distance therefrom by projecting pins or blocks 30 formedon or fixed to the lower face of arm 12 and which are intended to reston the edges of the plate described above.

[0261] The lower face of mask 10 comprises a series of oblique lanes (orramps) 32, which are mutually parallel and arranged in two transverserows that are mutually offset in a staggered pattern in the exampleshown. These lanes (or ramps) 32 extend parallel to the direction ofelectrophoretic migration and are all inclined in the same direction.Their lowest extremity comprises an orifice 34 for depositing thereagent on the analytical support. This orifice 34 is the lower orificeof a conduit or passage traversing the mask 10 over its whole thicknessand opening into the upper face of the mask via an orifice 36 with adiameter that is much larger than that of the lower orifice 34.

[0262] In one embodiment of the invention shown in FIGS. 4 to 6, theseorifices 34 and 36 are the ends of small cylindrical conduits with acircular cross section connected to each other via a truncated conicalconduit 38.

[0263] The mask holder 12 and snap fitted mask 10 are attached to guiderail 14, and so transverse adjustment using screw 22 can bring the rampsof the mask into vertical alignment with the sample migration lanes,which can be visualised by adding a suitable dye such as bromophenolblue to the deposited samples.

[0264] The mask can be manually swept over the top of the analyticalsupport using handle 26 or using the motorised means described above.

[0265] As shown diagrammatically in FIG. 3, a cover 40 can be placed onthe mask 10 and fixed thereon to close conduits 34, 36, 38 formed inmask 10 in a substantially sealed manner. A tube 42 on cover 40 opensabove the upper orifices 36 of these conduits and allows injection of asmall quantity of air between the mask and the cover, to exert apressure on the reagents contained in the conduits of the mask and tocause them to fall into the conduits to bring them into contact with theanalytical support.

[0266] The reagents can be deposited in the conduits of mask 10, theseconduits can be closed in a substantially tight manner by cover 40, themask 10/cover 40 assembly can be transported and placed above theanalytical support before using the reagents.

[0267]FIGS. 7 and 8 diagrammatically illustrate two variations of mask10:

[0268] that of FIG. 7 comprises 18 traversing conduits arranged in tworows that are parallel and offset in a staggered pattern from one row toanother;

[0269] that of FIG. 8 comprises two groups of six traversing conduits,the two groups being aligned over the length of the mask and eachcomprising five aligned conduits and one offset conduit.

EXAMPLES USING THE MASK OF THE INVENTION Example 1

[0270] Simultaneous Immunofixation of 9 Samples Using a Mobile Mask with18 Lanes (FIG. 4)

[0271] Manipulation was carried out using SEBIA's Hydrasys®electrophoresis instrument on a gel intended for immunofixation withdimensions of 0.7×83×101 mm.

[0272] To deposit samples on the electrophoresis support, we usedapplicators (French patent FR-A-2 671 290 and European patent EP-A-0 493996) comprising 18×3 mm teeth spaced 2 mm apart. Each sample wasdeposited on 6 consecutive teeth, and thus each applicator could deposit3 different samples on the electrophoresis gel, and 3 applicators wereused to obtain the 9 samples for analysis. The deposits were made on thegel using the Hydrasys® instrument, in 3 parallel rows respectivelylocated 18, 38 and 58 mm from the cathode edge of the gel.Electrophoretic migration was carried out at a controlled temperature of20° C. at a constant power of 20 W and for a period so that 31 volthours were accumulated.

[0273] Once migration was complete, the mobile mask of the inventionwith 18 lanes with the following geometrical characteristics wasinstalled: lane width 2.5 mm, lane length 7 mm, inter-lane distance 2.5mm, slope of lanes 5°. A row of 3 lanes (intended for the fixative) wasoffset by 5.5 mm with respect to the row of 15 lanes (intended for theantiserums).

[0274] The hollows in pins 20 of the guide rail were positioned on thetwo dogs carried on the migration plate of the Hydrasys® instrument.

[0275] The 18 lane mask was snap fitted into the mask holder 12, whichitself had been attached to the guide rail. The mask and its mask holderwere brought into abutment in the high position, i.e., on the anode sideof the gel. A dye, bromophenol blue, incorporated into the samplesdeposited on the gel, allowed the position of the electrophoretic laneson the analytical support to be visualised. Using transverse adjustmentmeans 20, 22, the lanes or ramps of the mask were brought into verticalalignment with the migration lanes of the samples.

[0276] The mask was then loaded by introducing the different reagentsrequired for immunofixation via the upper openings of the lanes (36), inan amount of 10 μl of reagent per lane and in the usual order: fixative,anti IgG, anti IgA, anti IgM, anti kappa and anti lambda. The fixativewas introduced beneath the 3 offset anode side lanes.

[0277] Once introduced between the lanes and the gel, these 10 μlreagent loads were distributed beneath each lane over about 5-6 mmbeyond the zones, anode side, that were to be revealed.

[0278] Once the mask had been loaded, it was displaced using the handle(26) by sliding along the guide rail. This sweep was carried outsmoothly without jerking at an approximately constant speed from thehigh position (anode side) to the low position (cathode side) of thegel, over a path of 63 mm. This sweep was carried out in about 3seconds.

[0279] Once the mask had arrived in abutment in the cathode position, asweep was carried out in the reverse direction under the sameconditions. These two sweeps were repeated once again. The entire amountof reagents initially introduced beneath the lanes had then beendeposited on the gel above the electrophoretic migration zones. The maskcould be withdrawn before the phase for incubating the reagents on thegel, carried out for 5 minutes at 20° C.

[0280] We then proceeded to the pumping, drying, washing, staining,destaining and drying steps using the usual immunofixation protocols.

Example 2

[0281] Simultaneous Immunofixation of 12 Samples using a Mobile 18 LaneMask (FIG. 4)

[0282] The procedure of the previous example was repeated, but 4 18tooth applicators were loaded with 3 samples per applicator. Using theHydrasys® instrument, deposits were made on the gel in 4 parallel rowsrespectively located 18, 33, 48 and 63 mm from the cathode edge of thegel. Migration was carried out for 28 volt hours at a constant power of20 W, at 20° C. The method was then as described for the previousexample.

Example 3

[0283] Simultaneous Immunofixation of 4 Samples Using a Mobile 12 LaneMask (FIG. 8)

[0284] The samples were deposited on the gel using applicators with 15×4mm wide teeth spaced apart by 2 mm, the applicators being loaded in anamount of 2 samples per applicator (sample n°1, teeth 2 to 7; samplen°2, teeth 9 to 14).

[0285] The Hydrasys® instrument was used to produce deposits on the gelin 2 parallel rows located respectively 23 and 53 mm from the cathodeedge of the gel.

[0286] Migration at a controlled temperature of 20° C. at a constantpower of 20 W was carried out until 42 volt hours had been accumulated.

[0287] Once migration was complete, the mobile mask of the inventionwith 12 lanes with the following geometrical characteristics wasinstalled: lane width 3.5 mm, lane length 7 mm, inter-lane distance 2.5mm, slope of lanes 5°. A row of 2 lanes (for loading the fixative) wasoffset by 5.5 mm with respect to the row of 10 lanes (for loading theantiserums).

[0288] The hollows in pins 20 of the guide rail were positioned on thetwo dogs carried by the migration plate of the Hydrasys® instrument. The12 lane mask was snap fitted into the mask holder 12, which itself hadbeen attached to the guide rail, and the assembly had been brought intoabutment in the high position.

[0289] Using the transverse adjustment means, the lanes of the mask werebrought (as described in Example 1) into alignment with theelectrophoretic migration lanes of the samples.

[0290] The mask was loaded by introducing 14 μl of reagent per lane.

[0291] The reagents were distributed as described in the precedingexamples by carrying out 4 sweeps with the mask.

[0292] The entire quantity of the reagents had then been deposited onthe surface of the gel and the mask was then withdrawn.

[0293] We then proceeded to incubation and to the pumping, drying,washing, staining, destaining and drying steps using the usualimmunofixation protocols.

Example 4

[0294] Carrying out a 36 IF Penta Technique Using an 18 Lane Mobile Mask(FIG. 4)

[0295] The IF penta technique is routinely used to detect the presenceof paraproteins in analysed samples in the form of monoclonal oroligoclonal immunoglobulin bands.

[0296] This technique is carried out by side-by-side developing for eachsample analysed of the total protein profile and the profile of allimmunoglobulins by carrying out immunofixation using a pentavalentantiserum, i.e., having anti IgG, anti IgA, anti IgM, anti kappa andanti lambda specificities.

[0297] Manipulation was carried out in this example using an agarose gelintended for immunofixation with dimensions 0.7×83×101 mm using a SEBIAHydrasys® electrophoresis instrument. Combs with 18×3 mm teeth spaced 2mm apart were used. Each sample for analysis was deposited twice side byside, i.e., 9 samples per applicator.

[0298] 4 applicators were used for the 36 samples.

[0299] The deposits were made on the gel using the Hydrasys® instrumentin 4 parallel rows respectively located 18, 33, 48 and 63 mm from thecathode edge of the gel. Migration was then carried out at a controlledtemperature of 20° C. at a constant power of 20 W to an accumulation of28 volt hours. The 18 lane mobile mask of the invention corresponding toFIG. 4 was then installed.

[0300] This mask was constituted by 2 rows of 9 lanes each, offset fromeach other by 5.5 mm. The 9 most anodic lanes were intended to receivethe fixative and the 9 other lanes were intended to receive thepentavalent antiserum. Each lane was 2.5 mm wide, with a length of 7 mm,an inter-lane distance of 2.5 mm and a slope of 5°.

[0301] The mask was snap fitted in the mask holder and brought intoabutment in the high anode side position.

[0302] The reagents were introduced in an amount of 10 μl/lane.

[0303] The procedure of Examples 1 to 3 was then followed.

1. A mask for depositing and distributing reagents on an analyticalsupport for biological samples, comprising: a lower surface and an uppersurface that are at least partially mutually parallel, separated by adistance constituting the thickness of the mask; one or more delimitedzones (lanes) located on the level of the lower surface of the mask andcomprising an element (32) that projects (projecting element) from thelower surface of the mask, each projecting element comprising a portionconstituting a slope with respect to a horizontal plane; associated witheach lane, an opening traversing the mask over the whole of itsthickness from an upper orifice (36) on the upper surface of the mask toa lower orifice (34), said lower orifice being located in the lane inthe proximity of the lowest point of the slope of the lane; the maskbeing such that the lane or lanes it comprises can hold reagents loadedinto each opening and deposited on the analytical support by capillaryaction between the lane and the surface of the analytical support facingwhich the mask is to be placed.
 2. A mask according to claim 1, suitablefor distributing reagents on an analytical support for biologicalsamples, comprising: a lower surface and an upper surface that are atleast partially mutually parallel, separated by a distance constitutingthe thickness of the mask; one or more lanes each comprising aprojecting element (32) of elongate shape emerging beneath the lowersurface of the mask, said projecting element comprising a portionconstituting a slope with respect to a horizontal plane; associated witheach lane, an opening traversing the mask over the whole of itsthickness from an upper orifice (36) on the upper surface of the mask toa lower orifice (34), said lower orifice being located in the lane inthe proximity of the lowest point of the slope of the lane; the maskbeing such that the lane or lanes it comprises can hold reagents loadedinto each opening and deposited on the analytical support by capillaryaction between the lane and the surface of the analytical support facingwhich the mask is to be placed.
 3. A mask according to claim 1, suitablefor distributing reagents on an analytical support for biologicalsamples, comprising: a lower surface and an upper surface that are atleast partially mutually parallel, separated by a distance constitutingthe thickness of the mask; one or more lanes each comprising aprojecting element (32) emerging beneath the lower surface of the mask,constituted by a protuberance in the shape of a truncatedparallelepiped, said projecting element comprising a portionconstituting a slope with respect to a horizontal plane; associated witheach lane, an opening traversing the mask over the whole of itsthickness from an upper orifice (36) on the upper surface of the mask toa lower orifice (34), said lower orifice being located in the lane inthe proximity of the lowest point of the slope of the lane; the maskbeing such that the lane or lanes it comprises can hold reagents loadedinto each opening and deposited on the analytical support by capillaryaction between the lane and the surface of the analytical support facingwhich the mask is to be placed.
 4. A mask suitable for depositing anddistributing reagents on an analytical support for biological samples,comprising: a lower surface and an upper surface that are at leastpartially mutually parallel, separated by a distance constituting thethickness of the mask; one or more delimited zones (lanes) located inthe lower surface of the mask and comprising an element (32) thatprojects (projecting element) from the lower surface of the mask, eachprojecting element comprising a lower surface and an upper surface thatare mutually parallel and parallel to the lower and upper surface of themask; associated with each lane, an opening traversing the mask over thewhole of its thickness from an upper orifice (36) on the upper surfaceof the mask to a lower orifice (34), said lower orifice being located inthe lane in the proximity of the lowest point of the slope of the lane,produced by inclining the mask with respect to the analytical support inthe position of use; the mask being such that the lane or lanes itcomprises can hold reagents loaded into each opening and deposited onthe analytical support by capillary action between the lane and thesurface of the analytical support facing which the mask is to be placed.5. A mask according to claim 1, characterized in that it is rigid orstiffened.
 6. A mask according to claim 4, characterized in that it isrigid or stiffened.
 7. A mask according to claim 1, in which the volumeof the opening is such that it can constitute a reservoir for the loadedreagents.
 8. A mask according to claim 1, in which the opening for eachlane traverses the thickness of the mask including the thickness of theprojecting element (32) in a perpendicular manner, the openingcomprising a portion in the shape of a truncated cone (38) terminated bya lower orifice (34) that is cylindrical in shape.
 9. A mask accordingto claim 4, in which the volume of the opening is such that it canconstitute a reservoir for the loaded reagents.
 10. A mask according toclaim 1, comprising a plurality of mutually parallel lanes, distributedover the length of the mask.
 11. A mask according to claim 4, comprisinga plurality of mutually parallel lanes, distributed over the length ofthe mask.
 12. A mask according to claim 11, comprising: a first seriesof mutually parallel lanes disposed in a first alignment; a secondseries of mutually parallel lanes that are parallel to the lanes of thefirst series, and forming a second alignment offset with respect to thefirst alignment.
 13. A mask according to claim 12, comprising: a firstseries of mutually parallel lanes disposed in a first alignment; asecond series of mutually parallel lanes that are parallel to the lanesof the first series, and forming a second alignment offset with respectto the first alignment.
 14. A mask according to claim 1, in which thelength of the slope of each lane coincides with the length of that lane.15. A mask according to claim 4, in which the length of the slope ofeach lane extends over the length of that lane.
 16. A mask according toclaim 1, for depositing each reagent in a quantity equal to or in therange 4 to 15 μl in each opening of the mask and holding said reagentsbetween the lanes of the mask and the analytical support by capillaryaction, when the mask is brought to a distance from the analyticalsupport of 2 mm or less from the point of the mask that is furthest fromthe analytical support and to a distance from the analytical supportequal to or in the range 0.1 to 0.5 mm from the point of the mask thatis closest to the analytical support.
 17. A mask according to claim 4,for depositing each reagent in a quantity equal to or in the range 4 to15 μl in each opening of the mask and holding said reagents between thelanes of the mask and the analytical support by capillary action, whenthe mask is brought to a distance from the analytical support of 2 mm orless from the point of the mask that is furthest from the analyticalsupport and to a distance from the analytical support equal to or in therange 0.1 to 0.5 mm from the point of the mask that is closest to theanalytical support.
 18. A mask according to claim 1, in which the lanesare separated from each other by a distance of 1.5 mm or more.
 19. Amask according to claim 4, in which the lanes are separated from eachother by a distance of 1.5 mm or more.
 20. A mask according to claim 1,in which the dimensions of the lanes and their spacing are such that thereagents held by them between the mask and the analytical support bycapillary action do not interact during deposition or distribution ontosaid analytical support.
 21. A mask according to claim 1, in which thelane width is 2.5 mm.
 22. A mask according to claim 1, in which thelength of each lane is in the range 6 to 7 mm.
 23. A mask according toclaim 1, in which the lane intended for the fixative is offset withrespect to the neighboring first lane by a distance of 5 to 7 mm.
 24. Amask according to claim 1, in which the slope of each lane forms anangle in the range 1° to 10° to a horizontal plane.
 25. A mask accordingto claim 1, in which each lane of the mask has the following dimensions:length: 3 to 15 mm; width: 1 to 10 mm; inclination of the slope: 1° to10° to the horizontal.
 26. A mask according to claim 1, associated withpositioning means intended to hold the mask in the proximity of thesurface of the analytical support close to which the mask will bebrought for deposition and distribution of reagents on the analyticalsupport.
 27. A device for depositing and distributing one or morereagents on an analytical support for biological samples, comprising: a)a mask (10) according to claim 1; b) means (12, 14, 16) for positioningand guiding the mask allowing the mask to be positioned so that the maskis held in the proximity of the surface of the analytical support andallowing the mask to be guided by sweeping the surface of the analyticalsupport in a horizontal plane parallel to the surface of said support toallow deposition and distribution of the reagents over each of thepredetermined zones of the analytical support coming into line with thelanes of the mask.
 28. A device for depositing and distributing one ormore reagents on an analytical support for biological samples,comprising: a) a mask (10) according to claim 1; b) means (12, 14, 16)for positioning and guiding the mask allowing the mask to be positionedso that the mask is held in the proximity of the surface of theanalytical support and allowing the mask to be guided by sweeping thesurface of the analytical support in an inclined plane with respect tothe surface of said support, to allow deposition and distribution of thereagents over each of the predetermined zones of the analytical supportcoming into line with the lanes of the mask.
 29. A device according toclaim 28, in which the means for positioning and guiding the mask (10)can establish a distance between the analytical support and the point onthe mask that is closest to said support in the range 0.1 mm to 0.5 mm.30. A device according to claim 28, in which the positioning and guidingmeans allow automatic displacement of the mask (10) along the analyticalsupport.
 31. A method for depositing and distributing one or morereagents on an analytical support comprising biological samples, themethod comprising the steps of: positioning a mask (10) according toclaim 1 in the proximity of the analytical support to deposit thereagent or reagents on the analytical support and hold them between saidsupport and the slope of the lane or lanes of said mask by capillaryaction; loading the reagent or reagents onto the mask (10) to depositthe reagent or reagents on the analytical support and hold them betweensaid support and the slope or slopes of said mask by capillary action;displacing the mask (10) by sweeping the surface of the analyticalsupport to distribute the reagent or reagents on the analytical supportin delimited zones of said support (termed incubation zones), thereagent or reagents being distributed in a quantity sufficient to allowtheir interaction with the constituents of the biological samplespresent on said analytical support.
 32. A method for depositing anddistributing one or more reagents on an analytical support comprisingbiological samples, comprising the steps of: loading the reagent orreagents onto a mask (10) to allow the reagent or reagents to bedeposited on the analytical support, and being held between said supportand the slope or the lane or lanes of said mask by capillary action;positioning a mask (10) according to claim 1 in the proximity of theanalytical support to deposit the reagent or reagents on the analyticalsupport and hold them between said support and the slope of the lane orlanes of said mask by capillary action; displacing the mask by sweepingthe surface of the analytical support to distribute the reagent orreagents on the analytical support in delimited zones of said support(termed incubation zones), the reagent or reagents being distributed ina quantity sufficient to allow their interaction with the constituentsof the biological samples present on said analytical support.
 33. Amethod according to claim 33, in which the mask is loaded with thereagent or reagents away from the zone of the surface of the analyticalsupport comprising the constituents of the biological samples.
 34. Amethod according to claim 34, in which the mask is loaded with thereagent or reagents prior to the step for positioning the mask in theproximity of the analytical support and in that the reagents aredeposited on the analytical support following an impulse resulting fromair pressure exerted on the mask, or by a mechanical junction betweenthe reagents and the analytical support, or by projecting the reagentsonto the support, or by brief contact between the mask and theanalytical support at the lowest point of the slope of the lane.
 35. Amethod according to claim 35, in which loading of the mask (10) with thereagent or reagents and/or displacement of the mask is in an automatedmanner.
 36. A method according to claim 32, in which the analyticalsupport is an electrophoresis support on which the constituents of oneor more biological samples have been separated by electrophoreticmigration.
 37. A method according to claim 37, in which the reagent orreagents are intended to allow immunofixation of the constituents ofbiological samples separated by electrophoresis.
 38. A method fordetecting the constituents of one or more biological samples byimmunofixation, comprising the steps of: carrying out electrophoresis onan electrophoresis support of the biological sample or samples toseparate out the constituents; depositing and distributing one or morereagents on an electrophoresis support, using a method according toclaim 32; incubating the biological samples separated by electrophoresiswith the reagent or reagents to allow their immunofixation.
 39. A kitcomprising: at least one mask according to claim 1; at least oneanalytical support.
 40. A kit according to claim 40, further comprising:reagents for immunofixation of the constituents of samples separated byelectrophoresis; a fixative for fixing each sample of the assembly ofconstituents separated by electrophoresis.
 41. A mask according to claim1, in which the reagents are loaded into the mask and are in the freezedried form.